Guys,Here is my problem, LNAV seems to over compensate on turns towards a specified waypoint, as indicated in the FMC. In the pictures I took, the aircraft came from the south of the pink line, the aircraft, I believe should have neared the pink line, then turned eastwards towards MSS32. However, the aircraft crossed the line, then attempted to turn back, as in picture 2 and 3, then again crosses the pink line southerly, and again attempts to correct. As it seems to me, I am making slow and distance consuming "s" turns all though the sky, taking forever to get to my waypoint. The aircraft starts south of the line to the waypoint, goes north, overcompensates to the south, and then to the north and so on... Hope someome can help me with this problem.http://forums.avsim.com/user_files/22578.jpghttp://forums.avsim.com/user_files/22579.jpghttp://forums.avsim.com/user_files/22581.jpghttp://forums.avsim.com/user_files/22583.jpg Much thanks in advance.Regards,

Please remember to follow forum guidelines and sign your posts.If you zoom in to the 10 mile range (or lower) you should notice that the aircraft is intercepting the the course and then correcting to stay on course. Since in your example the autopilot has chosen a high angle to intercept, as the course is intercepted, the autopilot must make a significant turn in the other direction to get back on course (due to the bank limits imposed on the autopilot system).This situation (in my IFR experiences) is not really what happens in real life. Typically ATC will vector you to intercept a specific waypoint on your route. If you are using the autopilot you would manually select the vector (using heading bug) to the waypoint and then intercept original course (as filed in your flight plan). Example after takeoff at KORD and vectors from Departure: UAL358: Chicago CTR UAL358 w/y passing FL210 for FL250 ATC: UAL358 Radar contact, turn left heading xx direct PLL then on course (or ...direct PLL to join the JXX...)I believe the autopilot is reacting correctly (like the real thing). I am not an NG driver, but on the GA aircraft I have flown when using GPS, and intercepting in a similar way, the autopilot acts the same as the NG. The autopilot selects an aggressive bearing to intercept the plotted course as soon as possible. It then has to correct again once the course is intercepted. Other flight sim aircraft models I own also have similar behavior.Hope this is helpful,George

A good idea would be in that case to reselect that waypoint in the legs page and again left LSK1 where it was, this would instruct the A/P to follow a direct course to it from present position and not from original track. That will avoid fish-tailing to get back on course.Regards,Bjorn

Thanks for the help guys!@ George, I did sign my post bud, it's in the signature ;-)Regards,

My apologies Neil. It helps if I actually scroll to the 'Bottom' of your message instead of just looking at the pictures! :-dohGeorge

No apologies needed mate, happens to me all the time :-)Regards,

Great Bjorn, thx for the tip!George

Dear Neil,In the pictures above you will observe that wind conditions are changing. From first to third by 30 degrees and then back to 119. Wind drift is a major factor whether in a Cessna or a jetliner. This explains what you see (WCA == wind correction angle).I should also inform you that the PMDG NG is probably the only (and I mean THE ONLY) simulated aircraft with dynamic turn anticipation using mapped data. There are cases, however, where a combination of wind change such as this (AP cannot forsee the future), or FSUIPC + FS delays regrettably trick the system. In this case it becomes just as good or bad as every other FS add on product out there.Regards,Vangelis============================================== E. M. Vaos Precision Manuals Development Group www.precisionmanuals.com==============================================

12kts of wind will not cause much wind correction angle with a TAS of 350kts. I don't need an E6B to tell me that.What is "mapped" turn anticipation? Lee Hetherington (KBED)